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Problem: Exaggerate symptoms of candida and other yeast-feeding infections.

What happens: According to Jackie Keller, founder of NutriFit and author of Body After Baby: A Simple, Healthy Plan to Lose Your Baby Weight Fast (Avery/ Penguin, $24.95), "Dried fruits are a concentrated source of naturally occurring fruit sugars that can exaggerate symptoms of candida and other yeast-feeding infections." Candida albicans is a yeastlike fungus that inhabits the intestines, genital tract, mouth, esophagus and throat. Under normal conditions, this fungus lives in healthy balance with the other bacteria and yeasts in the body. However, certain conditions can cause the bacteria to multiply out of control, and it can lead to a weakened immune system and an infection known as candidiasis.

"There are a host of candidiasis symptoms that vary from person to person and can include, but are not limited to, constipation, headaches, mood swings, persistent heartburn, and kidney and bladder infections," Keller says.

How much do you have to eat? "Everyone is different, so it's impossible to generalize, but I would think that since a 'normal' serving size is (about 1 ounce), having any more than twice what a serving size is supposed to be is having too much," Keller says.

Flax seed

Problem: Increased risk of prostate cancer.

What happens: Its high content of alpha-linolenic acids, or ALA, has made the ancient flax seed our modern miracle food, says Gloria Tsang of HealthCastle.com. "It offers a vegetarian alternative to provide omega-3 fatty acid and has been shown in many studies to offer heart-healthy benefits by lowering total cholesterol and low-density lipoprotein (LDL or 'bad') cholesterol levels. Flax seed may also help lower tri glycerides and blood pressure and keep platelets from becoming sticky, thereby reducing the risk of a heart attack."

However, a few studies have shown high concentrations of ALA to be linked to a higher risk of prostate cancer. Until more is known, men who are not vegetarians are recommended to choose fish sources for heart-healthy omega-3s instead, Tsang says.

How much do you have to eat? ALA is concentrated in oil form, so it's OK for men to eat the actual seeds, but until more studies are done, they should stay away from the oil form (flax seed oil and flax seed oil pills), Tsang says.

Carrots

Problem: Eating too many carrots might result in hypercarotenemia.

What happens: According to Maurice A. Ramirez, a Florida-based emergency room physician and founder of High Alert, "Excess beta carotene ingestion can cause yellow or orange discoloration of the skin and eyes that mimics jaundice and liver disease."

How much do you have to eat? The amount of beta carotene you must eat to turn orange depends on your size (body surface area). Originally, this condition was seen only in infants transitioning to puréed foods. In the 1950s, 1960s and 1970s, parents were told to introduce only one food at a time and feed it to the baby six times a day for a week. Because the first food was carrots the next was sweet potatoes and the third butternut squash, by week four the child was orange. "Fortunately, this is a benign problem that resolves over several weeks once the overconsumption of beta carotene stops," Ramirez says.

Barley, rye, wheat and sometimes oats

Problem: Gluten sensitivity or celiac disease.

What happens: "People who are sensitive or allergic to gluten, a protein found in barley, rye, wheat and sometimes oats, may experience diarrhea, lactose intolerance, iron deficiency and other malnutrition-related problems," says Lona Sandon, a professor of nutrition at the University of Texas Southwestern Medical Center at Dallas. Non-gastrointestinal symptoms include a dermatitis rash typically found on the elbows and knees."

How much do you have to eat? Any amount of gluten is a problem.

Here are two foods that cause benign changes:

Poppy seeds

Problem: Opiate-positive drug test.

What happens: Poppy seeds come from the poppy plant, the source of opium and other opiate drugs. "Sub-therapeutic amounts of opiates in the poppy seeds are metabolized in the same way as larger drug doses and excreted in the urine," Ramirez says.

How much do you have to eat? "Contrary to popular belief, the amount of poppy seeds on a bagel or a loaf of bread will not result in a positive drug test, nor will it excuse such a result. Poppy seed strudel, if the poppy seeds are ground and sautéed in butter for several hours to make the strudel paste and then eaten in large quantities, may result in a positive screening exam. However, confirmation with a 2-mono-amino-morphine test will make a drug-abuse source evident," Ramirez says.

Asparagus

Problem: Urine smells odd and takes on a slight green tinge.

What happens: "Asparagusic acid and thioesters in asparagus are excreted in the urine, creating the odor change and, when combined with other urine components, changing the color of the urine," says Ramirez. "Not everyone has the enzymes to convert asparagusic acid to an odor-forming compound. The presence or absence of the enzyme is a genetically controlled function and has no relationship to individual health."

How much do you have to eat? Even small amounts of asparagus can cause this effect, as can cabbage and Brussels sprouts. "This effect can be disconcerting but is harmless and resolves in a few hours," Ramirez says.